Editing Shell (projectile) (section)

===Chemical===
[[File:155mmMustardGasShells.jpg|thumb|right|155 mm artillery shells containing [[mustard gas|HD]] (sulfur  mustard) agent at [[Pueblo, Colorado|Pueblo]] chemical weapons storage facility – Note the colour-coding scheme on each shell.]]
Chemical shells contain just a small explosive charge to burst the shell, and a larger quantity of a [[chemical weapon|chemical agent]] or [[riot control agent]] of some kind, in either liquid, gas or powdered form. In some cases such as the [[M687]] Sarin gas shell, the payload is stored as two precursor chemicals which are mixed after the shell is fired. Some examples designed to deliver powdered chemical agents, such as the [[M110 155mm Cartridge]], were later repurposed as smoke/incendiary rounds containing powdered [[white phosphorus]].

Chemical shells were most commonly employed during the [[First World War]]. Use of chemical agents of all kinds has been forbidden by numerous international treaties starting with the 1925 [[Geneva Protocol]] (not to be confused with the [[Geneva Convention]]), with the 1993 [[Chemical Weapons Convention]] being the most modern treaty which also outlaws production, stockpiling and transfer of such weapons. All signatories have renounced the use of both lethal chemical agents and incapacitating agents in warfare.